Effect of crop root exudates on the size and stability of soil aggregate | 作物根系分泌物对土壤团聚体大小及其稳定性的影响

chinois. 采用土培试验将玉米和大豆植株根系分泌物添加到黑土中，25℃培养30d，研究根系分泌物对土壤水稳性团聚体大小和稳定性的影响。研究结果表明，作物根系分泌物添加到土壤中，显著提高土壤有机碳矿化率、土壤水溶性糖和多糖含量及水稳性大团聚体（〉1mm）比例（P〈O．05），显著提高水稳性团聚体稳定性（P〈O．05）。玉米和大豆根系分泌物对土壤结构特性影响趋势基本一致，玉米根系分泌物提高土壤稳定性的幅度显著高于大豆根系分泌物。培养1d时，添加玉米和大豆根系分泌物的土壤水稳性团聚体比例分别比对照增加2．38倍和1．71倍；培养30d时，添加玉米和大豆根系分泌物的水稳性团聚体含量分别比对照增加52．0％和28．4％。因此，新鲜的作物根系分泌物能快速黏结土壤颗粒，避免遭水破坏，保护团聚体，从而提高团聚体稳定性。[著者文摘]

anglais. The soil structural properties after addition of crop root exudates to the soil was studied through a soil culture experiment. Root exudates were collected from soybean （ Glycine max （ L. ） Merr. ） and corn （ Zea mays L. ） plants. Exudates were added to black soil which was incubated for 30 days at the temperature of 25 ℃. The effect of soybean and corn root exudates on soil aggre- gate size and its stability were conducted. The results showed that addition of crop root exudates to black soil increased significantly the mineralization of soil organic C, the content of soil water-soluble sugar and polysaceharide, and the proportion of biggest soil ag- gregate （〉1 mm） （P〈0. 05 ）, and resulted in a significant increase in soil aggregate stability （P〈0. 05 ）. The patterns of the changes of soil structure were very similar for additions of corn and soybean root exudates while the magnitude of the change in im- proving soil structural stability for the addition of corn root exudates was larger than that in the addition of soybean root exudates. Compared with the control, the proportion of water stable aggregates of soybean root exudates 1 d after the incubation was multiplied by 2. 38 and 1.71, respectively, and the proportion of water stable aggregates of soybean root exudates 30 d after the incubation was multiplied by 52.0% and 28. 4% , respectively. Therefore, the research suggests that freshly released exudates are able to stick very rapidly to soil particles and protect aggregates against water destruction, so it can enhance soil aggregate stability.